Asian elephants (Elephas maximus) demonstrate inhibitory control in a detour task

Inhibitory control-or the suppression of an impulsive, or prepotent, response in favor of a less obvious, but more effective behavior-is an important aspect of executive function, decision-making, and cognitive flexibility. Although elephants have large brains and behave flexibly, little is known about their capacity for inhibitory control, which limits our understanding of its evolution across species. We tested 16 (8M, 8F, 4-60 yrs) Asian elephants (Elephas maximus) at the National Elephant Institute in Thailand using a classic detour paradigm. Elephants first learned to reach their trunk around an opaque box to obtain food from a single opening. We then presented them with a transparent box with front-facing holes, where subjects needed to continue to reach around the box while inhibiting the impulse to reach straight toward the visible food and front-facing odor cues. We found that elephants performed similarly when detouring around both opaque and transparent boxes. This may indicate a strong ability to inhibit the impulse to reach straight forward, but may also indicate that the transparent box did not produce cues strong enough to elicit a prepotent response. In addition, we conducted trials in which we changed the box orientation so that elephants needed to inhibit using a previously learned response (i.e., a direction in which they had previously detoured) in favor of detouring in the newly changed direction. Here, we found evidence for a strong prepotent response: elephants' latency to detour around the box significantly increased when the box orientation changed. However, detour performance quickly improved across trials in which the orientation was constant, indicating effective inhibition of the previously learned response. Interestingly, performance in these trials worsened with age, revealing potential evidence for cognitive decline. This study provides some of the first evidence for inhibitory control in this species, and furthers our understanding of convergent cognitive evolution across distantly related taxa.